Feed device for screw-cutting lathes.



No. 649,447. Patented May l5. |900.'

J. GRIME.

FEED DEVICE FOR SCREW CUTTING LA'I 'HES.

(Application filed Sept. 9, 1899.)

(No Model.)

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UN'rnn STATES PATENT OFFICE.

JOHN GRIME, OF MINNEAPOLIS, MINNESOTA.

FEED DEVICE FOR SCREW-CUTTING LATHES.

SPECIFICATION forming part of Letters Patent No. 649,447, dated May 15,1900.

Application filed September 9, 1899. Serial No. 729,914. (No model.)

To all 1071,0727, it may concern:

Be it known that 1, JOHN GRIME, a citizen of the United States, residingat Minneapolis, in the county of I-Iennepin and State of Minnesota, haveinvented certain new and useful Improvements in Feed Devices for Screw-Cutting Lathes, of which the following is a specification.

My invention relates to devices employed in screw-cutting lathes andlike machines for feeding the tool or material in the operation ofcutting spiral threads.

The object of theinvention isimprovement of the method and means offeeding, whereby geometrically-perfect screws may be produced and theirpitch conveniently and accurately predetermined. This object isaccomplished by employing in place of the usual lead-screw and gears asa means for feeding the slide-rest a horizontally-adjustable guide-bar011 a carrier that is arranged to move transversely to the machine andsliding connections between such slide-bar and the tool-rest, (orwork-carrier,) whereby the transverse movement of the slide-bar servesto regulate the feed and determine the pitch of the screw.

My improvements are illustrated in the accompanying drawings, in whichFigure 1 is a side elevation of a lathe provided with my improved feeddevices. Fig. 2 is a detail, viewed from below, ofthetransversely-sliding frame and some of its connections. Fig. 3 is asectional view on the line a; m of Fig. 2, and Fig. 4 is a plan view ofa portion of the devices shown in Fig. 2.

- In the drawings, 1 designates the hollow bed of an ordinaryscrew-cutting lathe; 2, the head-stock; 3, the tail-stock, and 4 thesliderest. The slide-rest is adjustably attached. by means of aset-screw 5 or in any convenient way to a lead-rod 6, that extendslengthwise of the bed andis secured toaslide-block 7 near the head ofthe machine. Ways 8,provided on or beneath the bed, serve to guide thereciprocatory movements of the block longitudinally of the bed,andobviously such movements of the block will produce like movements of therod and slide-rest or other object to which the rod is connected. At theunder side of the block 8 is a similar block 9, the blocks beingpivot-ally connected by a pin 10, and the block 9 is arranged in ways11, formed lengthwise of a bar 12. This bar rests on a horizontal frameor plate 13, to which its inner end is pivoted, as at 11, so that it isadapted to be swung to different positions on the surface of the frame,aprojecting handle 15 on the bar serving to conveniently operate it. Toretain it in positions of adj ustm nt, a thumb-screw 16 or other devicemay be used in connection with a curved slot 17 or holes (not shown) atintervals, and graduations or other marks 18 may be employed to indicatethe degree of inclination of the bar from a base-line,to the end ofpredetermining the pitch of the screw to be cut.

The frame or carrier 13 may be of any desired construction adapting itto be reciprocated in guides or otherwise transversely of the bed. Asillustrated it is of rectangular form and arranged in ways 19, securedto the bed 1 for guiding its movements at right angles to thelongitudinal axis of the machine. To reciprocate it, there is attachedto its under side a rack 20, placed transversely to the bed, and in meshwith the rack is apinion 21, carried by a shaft 22, on which isagear-wheel 23 at the head of the machine, and a pinion 24; on the shaftof the head-stock drives the gear-wheel 23, its shaft, and connections.

The reciprocations of the frame 13 may be produced by gearingdifferently arranged from that shown or by sprocket-wheels and a chainsuitably connected to operate the pinion 21, it being only necessary forthe purposes of the invention that the frame 13 or its equivalent bereciprocated uniformly and conformably to the rotary movements of thehead-stock. The rotation of the pinion 21 moves the rack and frame atright angles to the bed, and as the guide-bar 12 moves laterally withthe frame the guides 11 will move the connected slide-blocks 9 and 7lengthwise of the machine, becauseof the engagement of the latter blockwith the longitudinal ways 8. The extent of such slide-block movementslengthwise of the machine relative to the dis- ICO the connectedslide-blocks lengthwise of the machine will obviously be greater for agiven lateral movement of the sliding frame than for the same extent offrame movement it the bar were adjusted more nearly in line with thedirection of the travel of the frame, as indicated by dotted lines inthe same view. The directions of movement of the frame 13 and theslide-blocks 7 and 9 may be said to be along the lines of a right-angledtriangle of which the guides 8 and 19 represent the sides and the guides11 the hypotenuse, and the adjustability of 'such hypotenuse to vary theobliquity of the anglesit forms with the sides (the guides 8 and 19)serves to regulate the extent of movement of the block 7 in its guidesrelative to the extent of the movement of the frame 13 in its guides,and in this way the advance movement of the slide-rest relative to therotation of the work-holder is regulated to determine the pitch of thescrew to be out. For example, if the guide-bar were set at an angle ofthirty degrees and in that position the machine were adapted to out,say, six threads to the inch and if when the bar were adjusted to anangle of five degrees the threads cut would be, say, sixty to the inch,then obviously by setting the bar at the proper intermediate point anydesired pitch of thread between the limits named could be produced.

The devices shown and described are obviously capable of considerablevariation both as to specific construction and their arrangement withoutchange of the mode of operation, and as I believe my invention to bebroadly novel I do not wish to restrict my claims to such specificstructures or arrangement.

What I claim is- 1. In a screw-cutting lathe, a lead-rod, a slideconnected thereto and guided parallel therewith, a second slidepivotally connected to the first, an inclined guide therefor, a carrierto which the latter guide is adjustably connected, a guide for thecarriage at right angles to the guides for the lead-rod slide, and meansfor reciprocating said carrier in its guides, substantially as setforth.

2. In a screw-cutting lathe, a feed device comprising a slide guided tomove lengthwise of the bed, a second slide pivotally connected to theformer and guided by an inclined guide, a carrier guided crosswise ofthe bed and to which the inclined guide is adjustably connected, andmeans for reciprocating said carrier in its guides to operate the feeddevice, substantially as set forth.

3. In a screw-cutting lathe, a feed device comprising superposed pivotedslides, fixed guides extending lengthwise of the bed for one of theslides, an adjustable inclined guide for the other slide, a carrier towhich one end of the latter guide is pivoted to enable its inclinationto be varied, guides for said carrier at right angles to said fixedguides, and means for reciprocating said carrier in its guides,substantially as set fort-h.

4. In a screw-cutting lathe, a feed device comprising superposed pivotedslides, fixed guides extending lengthwise of the bed for one of theslides, an adjustable inclined guide for the other slide, a carrier towhich one end of the latter guide is pivoted, means for adjustin g ithorizontally about its pivot for varying its inclination andforindicating the degree of its inclination, guides for said carrier atright angles to said fixed guides, and means for reciprocating saidcarrier in its guides, substantially as set forth.

5. In a screw-cutting lathe, the combination with the head-stock andtool-holder, of a lead-rod for the latter, a slide connected to the rod,guides therefor, a second slide piw otally connected to the former, aninclined guide therefor, a carrier to which the latter guide is adjustably connected, a guide for the carrier at right angles to the guidesfor the lead-rod slide, and cooperating mechanism for suitably rotatingthe head-stock and moving said guide-carrier in its ways, substantiallyas set forth.

In testimony whereof I have hereunto set my hand this 4th day ofSeptember, 1899.

JOHN GRIME. In presence of M. F. HARRISON, P. H. GUNcKEL.

